1. Field of the Invention
This invention relates to a mining machine and a method of mining and more particularly to the boom structure of a mining machine that rotatably supports a cutter drum for rotation of the drum to convey dislodged material over the cutter drum and into a hopper portion of the boom where the hopper directs the dislodged material onto a conveyor that transports the dislodged material rearwardly on the mining machine.
2. Description of the Prior Art
A conventional drum-type continuous mining machine employed in underground mining operations includes a boom member that extends forwardly from the mining machine body portion. The boom member includes a pair of arm members that are mounted adjacent opposite sides of the longitudinal center line of the machine. By operation of hydraulically controlled piston cylinder assemblies, the boom arms are arranged to pivot upwardly and downwardly.
U.S. Pat. Nos. 3,712,678 and 3,774,969 illustrate examples of cutter drums that are rotatably mounted transversely on the front ends of the boom arms. An endless conveying chain extends longitudinally along the center line of the machine in a trough. The conveyor extends from a receiving end the length of the machine to a discharge end which includes a pivotal section that extends rearwardly from the mining machine.
The receiving end of the continuous conveyor is operatively associated with a gathering device. The conventional gathering device includes a gathering platform that extends transversely across the front of the mining machine and tapers rearwardly to the receiving end of the conveyor as disclosed in U.S. Pat. Nos. 2,703,244 and 3,328,087. The gathering arms, as illustrated in U.S. Pat. No. 3,328,087, are rotatably mounted adjacent the transverse forward edge of the gathering platform. The gathering arms rotate in opposite directions to convey the dislodged material rearwardly from the gathering platform onto the receiving end of the conveyor as the mining machine advances during the material dislodging operation.
In order to effectively convey the dislodged material from the gathering platform onto the receiving end of the conveyor a plurality of gathering arms must be spaced transversely across the width of a gathering platform on opposite sides of the receiving end of the conveyor. It is important that the gathering arms be positioned as closely as possible to the lateral edges of the gathering platform to convey the material deposited thereon onto the receiving end of the conveyor.
It is the conventional practice to drivingly connect the gathering arms so that the gathering arms or in the case of gathering discs rotate in a direction to convey the material inwardly from the platform lateral edges and rearwardly onto the receiving end of the conveyor. Generally the drive mechanisms for the gathering arms include one or more motors mounted on the gathering platform. Suitable drive gearing connects each motor to one of the gathering arms on each side of the conveyor. The other gathering arms on each side of the conveyor are drivingly connected thereto by additional gearing arrangements such as a drive shaft and a worm drive mechanism to transmit rotation from one gathering arm to the other gathering arm on each side of the conveyor. It is also known to drivingly connect one pair of gathering arms on one side of the conveyor to the pair of gathering arms on the other side of the conveyor.
The drive connections to the gathering arms and the means for rotatably supporting the gathering arms on the gathering platform are quite complex. Due to their complexity malfunctions commonly occur which require their repair in order to continue the continuous mining operation. Therefore, there is need to provide an improved material conveying device and method associated with a continuous mining machine that eliminates the complexity of the conventional motor driven gathering arms on a gathering platform.